Thermally insulated constructions are used for example in the form of a freezer house, wherein consumer ice cream products are being frozen, the process of which has been a widespread and well-known process for many years. In such a process, the ice cream products are placed on a series of product plates that are conveyed by means of a chain conveyor in a rack. During the process time, e.g. the time that it takes for an ice cream product to be conveyed through the freezer house, which time may be variable but as an example may be 25 minutes, cold air having a temperature of circa minus 40° C. is blown over the products, which thereby are being cooled and frozen. The cold air is provided by means of a refrigerator arrangement, which has evaporators placed inside the freezer house, where a refrigerant fluid flows through the evaporators and where fans are blowing air over the evaporators.
Such a freezer house is usually built having an insulated floor, insulated walls, an insulated ceiling and one or more insulated doors. The outer side of the house can be covered by plates of stainless steel, of painted steel or plastic plates. Often, the outer side of the house is integrated in the elements that make up floor, the walls and the ceiling as the elements may be prefabricated panels.
The freezer houses may vary in size from small houses with dimensions of a few meters to large houses having a length and width of more than 10 meter and with a considerable height. Decisive for the size and the ratio between length, width and height are both the need and/or desire for a certain capacity and consideration of the floor space that is available.
Freezer houses may be designed at least partly with stainless steel inner cladding. In a simple design of such a freezer house only a bottom tray is made of stainless steel, which bottom tray covers the floor and reaches a small distance up along the sides of the freezer house.
Where high demands are made as regards food product safety, a stainless steel inner cladding is used. The stainless steel inner cladding can cover floor, walls and ceiling and can be made with continuous welding, e.g. seam welding of the joints to make up a completely closed unit. Thus, it is avoided that water and product residues may contact the insulating material, which otherwise would represent a risk of resulting undesired growth of bacteria or growth of other undesired matter. Furthermore, the cleaning procedure and subsequent drying of the freezer house is thereby simplified.
However, such prior art freezing houses and freezing constructions are associated with a number of drawbacks and disadvantages. For example, a normally used method of fabricating the freezer houses with stainless steel inner cladding comprises fabricating elements for the house, e.g. the outer parts for the house, and elements for the inner cladding separately and assembling these at the site. Such a prior art method is characteristic in that the setting up of a freezer house demands both considerable time and resources in that a relatively large number of working hours is required. In addition to this, such a prior art method causes that the product manufacturer, e.g. a consumer ice cream manufacturer, must accept that the production area is not usable while the setting up is performed. Also in the setting up period other disadvantages follow in connection with special shielding and cleaning processes, which are required in order to ensure the food product safety in production areas in the vicinity of the setting up area.
The setting up or erecting includes a number of very difficult sub-processes as regards craftsmanship and often the quality of the house as such deviates from the ideal quality as regards such issues as evenness of the bottom tray, finish of welding, etc. Other flaws which may primarily be of cosmetic character will also result from such a setting up that is performed at the actual site. Lack of evenness of the bottom tray can cause a lack of comfort when walking on the bottom tray and furthermore a more difficult draining after wash since the water will remain in puddles on the bottom tray. Often, it will not be possible to achieve the specified evenness in such prior art processes, which thereby requires that a compromise must be settled between the builder of the freezer house and the customer.
Even further, in connection with a part of prior art designs there is a risk of melting a part of the insulating material during the welding processes, when setting up the construction. Aside from the immediate fire risk that is caused, such a melting of the insulating material will also provide continuous problems with reduced insulating capability and undesired voids in the insulation. Such undesired voids in the insulation material will cause a subsequent risk of fluid accumulation in the insulation and further damage to the insulation caused by freezing of the fluid.
An example of a prior art insulated freezer tunnel construction is disclosed in U.S. Pat. No. 3,472,570, which relates to a modular construction. This document describes for example a construction, where stainless steel inner skin plates are welded together to form a channel-shaped inside jacket and where stainless steel outer skin plates are welded together to form a channel-shaped outside jacket. During assembly, the channel-shaped inside jacket is fitted within the channel-shaped outside jacket and held in position in relation to each other. Then, insulation in the form of polystyrene blocks is placed and voids are filled with foamed-in-place polyurethane. As it will be understood, such a construction is associated with a number of drawbacks as mentioned above, e.g. that the construction and setting up has to be made at the actual site, that the setting up is labour intensive and that the setting up requires that the actual space, e.g. a production area, is not usable for a considerable time while the setting up is performed.
Thus, there is a need for an improved design of such freezer constructions, freezer houses, freezer tunnels. etc.
Furthermore, there is a need for providing such an improved design and construction, whereby the time used for setting up the construction is reduced.
Even further, there is a need for such an improved design and construction, whereby the requirements as regards special skills of the workers setting up or erecting the construction are reduced.
Furthermore, there is a need for such an improved design and construction, whereby the setting up, erecting, etc. is facilitated, such that quality standards are fulfilled, e.g. including that                a satisfactory evenness of the floor in the construction is ensured, that        connections, welding seams, etc. have a good finish and quality, and that        an intact insulation of the construction is ensured.        
These and other objects are achieved by the invention as explained in further detail in the following.